Climate Change Thins Ozone Layer

During the 2004-2005 winter, the ozone layer reached the thinnest level ever recorded, according to a study by Cambridge University and reported April 27 in the

Guardian newspaper. “We thought things would start to get better because of the phasing out of CFCs and other chemicals because of the Montreal protocol,” says Cambridge Professor John Pyle, “but this has not happened.” The thinning is blamed not on pollution but on climate change, which has increased the number of stratospheric ice clouds in the winter. These clouds foster chemical reactions that destroy ozone. The ozone layer protects Earth’s surface from the sun’s ultraviolet rays. According to the United Nations, skin cancer rates rise 2–3% for every 1% thinning of the ozone layer. Thinning of the ozone layer also reduces the rate of photosynthesis in plants, potentially reducing the yield of crops, and it kills phytoplankton, which store carbon in the ocean, among other ecological consequences.